Peptidases released by necrotic cells control CD8+ T cell cross-priming
Jaba Gamrekelashvili, … , Firouzeh Korangy, Tim F. Greten
Jaba Gamrekelashvili, … , Firouzeh Korangy, Tim F. Greten
Published October 8, 2013
Citation Information: J Clin Invest. 2013;123(11):4755-4768. https://doi.org/10.1172/JCI65698.
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Research Article Immunology

Peptidases released by necrotic cells control CD8+ T cell cross-priming

Abstract

Cross-priming of CD8+ T cells and generation of effector immune responses is pivotal for tumor immunity as well as for successful anticancer vaccination and therapy. Dead and dying cells produce signals that can influence Ag processing and presentation; however, there is conflicting evidence regarding the immunogenicity of necrotic cell death. We used a mouse model of sterile necrosis, in which mice were injected with sterile primary necrotic cells, to investigate a role of these cells in priming of CD8+ T cells. We discovered a molecular mechanism operating in Ag donor cells that regulates cross-priming of CD8+ T cells during primary sterile necrosis and thereby controls adaptive immune responses. We found that the cellular peptidases dipeptidyl peptidase 3 (DPP-3) and thimet oligopeptidase 1 (TOP-1), both of which are present in nonimmunogenic necrotic cells, eliminated proteasomal degradation products and blocked Ag cross-presentation. While sterile necrotic tumor cells failed to induce CD8+ T cell responses, their nonimmunogenicity could be reversed in vitro and in vivo by inactivation of DPP-3 and TOP-1. These results indicate that control of cross-priming and thereby immunogenicity of primary sterile necrosis relies on proteasome-dependent oligopeptide generation and functional status of peptidases in Ag donor cells.

Authors

Jaba Gamrekelashvili, Tamar Kapanadze, Miaojun Han, Josef Wissing, Chi Ma, Lothar Jaensch, Michael P. Manns, Todd Armstrong, Elizabeth Jaffee, Ayla O. White, Deborah E. Citrin, Firouzeh Korangy, Tim F. Greten

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Figure 4

F37–45 characterization.

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F37–45 characterization. (A and B) Chromatographic fractions (see Figu...
(A and B) Chromatographic fractions (see Figure 2E) were added to CFSE-labeled OT-I splenocytes in the presence of 20 μg/ml OVA and F9–23. Proliferation and IFN-γ expression of CD8+ T cells was analyzed after 48 hours. Data show 1 representative of 2 independent experiments. (C and D) Splenic CD11c+ DCs (5 × 104) were preincubated with F9–23 and 20 μg/ml OVA with or without F37–45 for 4 hours. DCs were then washed, and purified CFSE-labeled OT-I CD8+ T cells (1 × 105) were added and incubated for 44 hours in the presence of F37–45 and/or F9–23 plus OVA, as indicated. Proliferation of Ag-specific CD8+ T cells was determined. (E and F) 20 μg/ml OVA protein was incubated with F37–45 overnight at 37°C and subsequently heated at 70°C for 1 hour as indicated. Samples were added to the CFSE-labeled OT-I cells in the presence of F9–23, and CD8+ T cell activation was determined after 48 hours. Results are representative of 3 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, 1-way ANOVA with Dunnett’s multiple-comparison test (D) or Student’s t test (E and F).